A Micro Sievert (µSv) is 1 millionth of a Sievert. A milisevert (mSv) is 1/1000 of a Sievert. 1 mSv = 10 rem (the older unit of measure)
A Sievert is a measure of radiation dose, taking into consideration the type of emission and how much damage it does to tissue.
Just living a normal life standing around, your body gets around 2400 µSv per year. Getting a mammogram is about 300 µSv (getting unneeded mammograms is more than just the cost)
If you get more than 250 mSv (250,000 µSv) in a day, you start to have symptoms. If you get 1000 mSv (1 Sv) in a day, you’re going to have serious damage to your health, but you may survive.
If you get 6000 mSv (6 Sv) in a day, you’re probably going to die.
If you get 10,000 mSv (10 Sv) in a day, you’re not reading this.
Following the explosion of Reactor 2, the radiation level at the plant was temporarily 8,217 µSv per hour (8.2 mSv or .008 Sv)
One mSv = 100 millirem.
You are correct.
I typed “1 mSv = 10 rem (the older unit of measure)”
What I mistyped should have said “10 mSV = 1 rem”
Be sure I don’t set the controls of your xray machine.
http://www.jplabs.com/html/units_of_radiation.HTM
0.001 rem = 1 mrem = 0.01 mSv
0.01 rem = 10 mrem = 0.1 mSv
0.1 rem = 100 mrem = 1 mSv = 0.001 Sv
1 rem = 1000 mrem = 10 mSv = 0.01 Sv
10 rem = 100 mSv = 0.1 Sv
100 rem = 1000 mSv = 1 Sv (Sievert)
1000 rem = 10 Sv
So what do you think is the significance of the various readings they’re taking?
Not being in the field, I hadn’t heard of a Sievert until yesterday. Rems were all I knew about since I went to school in the 70s – and the Sv was created in the late 1970s.
Maximum allowed dose for nuclear workers in the US is 5 rem, or .05 Sv. In Japan they’re reporting a dose of about 800 mrem. That’s pretty hot, but not unheard of- when you encounter that during maintenance activities in a regular plant you rig lead shielding to knock the radiation level down. The real question is WHERE is that dose being measured? Is it a contact dose with the primary containment wall or the floor around it, or is it an airborne dose at the plant boundary? If the latter I’d be seriously concerned. If the former, not so much.
I’m listening to the live TV signal…
They bailed when the reading at the gate hit 6000 uSv… it has fallen back to 2-3k uSV….. it may be the reason was reactor #3 ruptured, but they’re not sure…. the spent fuel rods in #4 have caught fire again.
How much does it matter with “Dosage rate” vs total dosage?
My assumption is if you get a lot of radiation but over a long period of time, you’ll have long term issues (cancers, destruction of bone marrow, etc…) where as a high rapid dose causes immediate health problems and impairs your ability to function
Sounds like they had a plume release from the #3 reactor. It temporarily raised radiation readings at the site boundary (gate) and then dispersed.
Back in the heyday of atomic testing scientists believed there was a “threshold dosage” below which there was no health impact. In the 1970s health physicists convinced everyone that any amount of radiation is harmful on some level- i.e., going to the beach is riskier than staying indoors.
Radiation causes cell damage. Cells that are undergoing mitosis are particularly susceptible. Therefore you don’t want women who might be pregnant or children around radiation areas. The body can usually repair cell damage that occurs over a long period of time. High levels of radiation accumulated over a short period are much harder for the body to repair. Regarding cancers, it’s all a matter of probabilities. A certain percentage of the population will get cancer regardless. A Chernobyl style radiation release will statistically increase that percentage, but rarely will you be able to point to any one case and say with certainty that “this person got cancer because of Chernobyl.”
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